Terminal, base station, and communication method

Abstract

This terminal includes a receiving circuit for receiving a synchronization signal, and a control circuit for determining a correspondence relationship between a synchronization signal block transmission position and a synchronization signal block index, wherein the control circuit changes the correspondence relationship between the synchronization signal block transmission position and the synchronization signal block at a first reception timing of the synchronization signal block and a second reception timing thereof.

1 . A terminal, comprising:
 reception circuitry, which, in operation, receives a synchronization signal; and   control circuitry, which, in operation, determines a correspondence relation between a transmission position of a synchronization signal block and an index of the synchronization signal block, wherein   the control circuitry changes the correspondence relation between a first reception timing and a second reception timing of the synchronization signal block.   
     
     
         2 . The terminal according to  claim 1 , wherein
 the control circuitry changes the correspondence relation by shifting the index of the synchronization signal block with respect to the transmission position of the synchronization signal block by a fixed amount.   
     
     
         3 . The terminal according to  claim 1 , wherein
 the control circuitry changes the correspondence relation by shifting the index of the synchronization signal block with respect to the transmission position of the synchronization signal block depending on a system frame number.   
     
     
         4 . The terminal according to  claim 1 , wherein
 the control circuitry reverses the correspondence relation of the index of the synchronization signal block with respect to the transmission position of the synchronization signal block between the first reception timing and the second reception timing.   
     
     
         5 . The terminal according to  claim 1 , wherein
 the control circuitry changes the correspondence relation by inputting a system frame number into a pseudo-random number expression.   
     
     
         6 . The terminal according to  claim 1 , wherein
 the control circuitry changes the correspondence relation using a system frame number with reference to a table indicating the correspondence relation for each system frame number.   
     
     
         7 . The terminal according to  claim 1 , wherein
 the control circuitry changes the correspondence relation using a cell identifier.   
     
     
         8 . The terminal according to  claim 1 , wherein
 using a cell identifier or information included in a System Information Block (SIB), the control circuitry switches a changing method for changing the correspondence relation.   
     
     
         9 . The terminal according to  claim 2 , wherein
 based on information included in a System Information Block (SIB), the control circuitry changes the fixed amount of the shifting.   
     
     
         10 . The terminal according to  claim 3 , wherein
 based on information included in a System Information Block (SIB), the control circuitry changes a shift amount of the shifting.   
     
     
         11 . The terminal according to  claim 1 , wherein
 the control circuitry changes the correspondence relation further based on a physical downlink control channel (PDCCH) or a physical downlink shared channel (PDSCH).   
     
     
         12 . A base station, comprising:
 transmission circuitry, which, in operation, transmits a synchronization signal; and   control circuitry, which, in operation, determines a correspondence relation between a transmission position of a synchronization signal block and an index of the synchronization signal block, wherein   the control circuitry changes the correspondence relation between a first transmission timing and a second transmission timing of the synchronization signal block.   
     
     
         13 . A communication method, comprising steps performed by a terminal of:
 receiving a synchronization signal;   determining a correspondence relation between a transmission position of a synchronization signal block and an index of the synchronization signal block; and   changing the correspondence relation between a first reception timing and a second reception timing of the synchronization signal block.   
     
     
         14 . A communication method, comprising steps performed by a base station of:
 transmitting a synchronization signal;   determining a correspondence relation between a transmission position of a synchronization signal block and an index of the synchronization signal block; and   changing the correspondence relation between a first transmission timing and a second transmission timing of the synchronization signal block.